Firefly and PC GAMESS-related discussion club

both X and Y are Nvir by Nocc matrices. Here Nvir is the number of virtual orbitals and Nocc is the number of active (i.e. non-core)occupied orbitals.

Kind regards,Alex Granovsky

On Wed Aug 12 '15 2:38pm, Siddheshwar Chopra wrote-------------------------------------------------->Dear Sir,>I have got the PUNCH file now from TDDFT output file.>I was seeing the $TDVEC group. It was told that there are 2*NSTATE records in the PUNCH file. In my case, NSTATE=10. I found only 10 records. Some of the text is below:

>Here as you said, "X" and "Y" are mentioned alternatively, X from 1st line onwards. I am unable to understand the size of the matrix (X or Y). Here "X" has 5 numbers. How to visualize this matrix? >Also, NVIR and NOC were talked about. Are these the "number of alpha and beta orbitals"? In this case it is 206 then? >Please elaborate about the construction of matrix. In case if PUNCH file is needed, I will send it privately, if only you permit.

>>Kind regards,>>Alex Granovsky>>>>>>On Mon Sep 29 '14 11:49am, Siddheshwar Chopra wrote>>--------------------------------------------------->>>Dear Alex,>>>Sorry for asking you again. There is a relation between transition density and transition dipole. So please pardon me if I ask:: Will extracting Transition dipole moment matrix serve the purpose of pointing out "spatial location of the transition from ground to excited state"? It is a NSTATE*NSTATE matrix as you told too.

>>>Kind Regards,>>>>>>>>>>>>>>>>>>>On Mon Sep 29 '14 11:13am, Siddheshwar Chopra wrote>>>--------------------------------------------------->>>>Dear Alex,>>>>Thank you for the detailed explanation. I really need a TDDFT PUNCH file now to understand what you have suggested. I will get back once I extract this matrix.>>>>In the meanwhile has anyone got a program for this extraction? It would be a great help.

>>>>>>>I would be really grateful if you could throw some light on the transition density matrix calculation. Is it possible to determine the matrix from TDDFT output file? IF yes then I would attach one file. Kindy let me know Sir.

>>>>>No, it is impossible to compute 1-P TDM (one-particle transition >>>>>density matrix) based only on the information found in the output >>>>>file.

>>>>>>>>Dear Pavlo Sir and Alex Sir,>>>>>>>>Thank you so much for the useful information. Alex sir I am really happy to know that it is possible to find TDM from PUNCH file (from TDDFT calc.). I would request you to elaborate the process for the same. Right now I dont have any punch file with me. Can you explain with the help of any punch file? Once that is clear, I will look for the program.

>>>>>The required information that can be extracted from the PUNCH file >>>>>is the content of the $VEC group and $TDVEC group. Each $VEC group >>>>>contains current molecular orbitals. The $TDVEC group contains X >>>>>and Y components of the TDDFT eigenvectors. For hybrid DFT, X >>>>>component is written first, then Y component follows. These records >>>>>are repeated for each root of TDDFT i.e. there are 2*NSTATE records >>>>>in total. As to individual record, it contains NVIR*NOC elements, >>>>>where NVIR is the number of virtual orbitals and NOC is the number >>>>>of active occupied orbitals i.e. the number of occupied orbitals >>>>>minus number of frozen core MOs. These numbers form matrices X >>>>>and Y, with virtual orbital index running first, then occupied >>>>>orbital index.

>>>>>Once you extracted X and Y matrices, the transition density matrix >>>>>in MO basis is simply sum of X and Y blocks: Tmo = X+Y. If you need, >>>>>you can convert it into MO basis set using the following equation:

>>>>>

Tao = S*V * Tmo * (S*V)-dagger

>>>>>where V are the matrix of MO coefficients and S is the matrix of >>>>>overlap integrals. The latter can be printed out by running >>>>>Firefly with exetyp=INT1

>>>>>>>>Also, Sir I found that transition dipole moment matrix in the TDDFT o/p file is of the size NSTATE X NSTATE. Can you explain how to analyse this? I find the x,y,z data corresponding to an i,j element.

>>>>>This is a matrix of transition dipoles between states Si and Sj.>>>>>This information can be used, for instance, to compute >>>>>two-photon absorbance (TPA)cross-sections using sum over states >>>>>approach (SoS)

>>>>>> Does the magnitude of this dipole moment = sqrt(x^2+y^2+z^2)?

>>>>>Yes it is (note in the printout atomic units are used throughout).